Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the input device determines the presence, location and/or motion of one or more input objects. Proximity sensor device may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones). Increasingly, proximity sensor devices are used in media systems, such as CD, DVD, MP3, video or other media recorders or players.
In the past, some proximity sensor devices have had limited ability to distinguish between the actions of a single input object and the actions of multiple input objects in the sensing region. For example, some past proximity sensor devices have had difficulty in determining that a user has lifted one finger from the sensing region, and placed down a second finger shortly thereafter. In such cases, the proximity sensor device may instead incorrectly determine that the sensed object positions reflect the movement of a single input object across the sensing region. In other cases, the proximity sensor device may incorrectly determine a user has lifted one finger and placed a second, when in fact the user has simply moved the same finger rapidly across the sensing region. In either case, the proximity sensor device may initiate an undesirable user interface action in response to the incorrect determination.
For example, some proximity sensor devices may have specially defined portions of the sensing region that provide specific interface functions. In some implementations these portions of the sensing region may be considered to be a “virtual button”, where a user “tapping” on the virtual button initiates the specified function. In such cases the virtual button region may also be used for other user interface actions. To give one specific example, during a cursor control operation, a user moving an object across the sensing region may cause cursor movement. When the object moves into the button region the sensor device should interpret that as continued object motion, and the sensor device should cause continued cursor motion in response. However, if the sensor device were to instead interpret the presence in the virtual button zone as the user now “tapping” the virtual button, the sensor device would incorrectly cease cursor control and activate the corresponding button function instead. Conversely, a user tapping on the virtual button shortly after having moved another object across the sensing region could be incorrectly interpreted by the device as continued object motion across the sensing region. In this case, the sensor device would incorrectly cause cursor motion instead of activating the button function.
In each case, unintended actions are generated and the user of the sensor device is likely to be inconvenienced and annoyed. For example, such results may cause the cursor to jump when it is intended to be stationary, requiring the user to reposition the cursor before tapping the virtual button again.
Thus, what is needed are improved techniques for more reliably determining if sensed object positions correspond to a single object or multiple objects in a sensing region of a proximity sensor device. Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.